In U.S. Pat. No. 4,123,262, I disclose silverless gold base alloys which do not discolor porcelain. The presence of silver in a dental gold alloy used for preparing baked-on porcelain to gold dental restorations often produces staining of the porcelain at the juncture of the porcelain and alloy. The silverless alloys of the present invention are similar in working characteristics to the alloys disclosed in U.S. Pat. No. 4,123,262, but are less costly due to a significant reduction in alloy gold content. The gold content however, is still present in the present alloys in sufficient quantities such that the alloys require no special manufacturing procedures or equipment for their fabrication.
No transition metals (e.g., iron, cobalt, nickel, copper) are included in the present alloys to produce a dark oxide upon heating, thereby reducing processing time since a dark oxide requires removal prior to application of porcelain to the restoration device. The absence of dark oxide formation in my alloys maintains the shade fidelity of the porcelain since the alloy substrate is not continually darkening during porcelain firing.